Once installed the Facebook and Instagram App to connect FB and Meta Ads accounts, which will automatically install the Meta Pixel and Conversion API to track the events.
Do we need to manually set up conversion tracking for purchase events separately?
No, you don’t need to manually set up conversion tracking for purchase events separately. Installing the Facebook and Instagram App to connect your FB and Meta Ads accounts automatically sets up the Meta Pixel and Conversion API to track events, including purchase events.
This should handle all necessary tracking for you.